An Uncommon Affaire
by Cumberbatch Critter
Summary: The Personal Blog of Dr John H Watson: Should I be worried? My best friend has taken my wife out on a date. A real date. At a restaurant. With a reservation. I've literally no part in this decision, but... at least it's for a case. It is for a case, after all. It sure better be a case, or, so help me, Sherlock...
1. Chapter 1

**An Uncommon Affaire**

"So, we just go in undercover-"

"As a couple."

"Undercover as a couple," Mary continued. "So that these people don't know you're actually on to them."

"Yes," Sherlock clarified, fingers steepled.

"I don't like it," John said, tightening his grip around Mary's hand.

Mary smiled and looked at him. "Are you jealous?" she asked.

"Honestly, John, I'm not trying to seduce your wife," Sherlock muttered. "It's a simple enough exercise."

"I still don't see why I can't wear a wire," John retorted.

"Wires are tedious. These type of people are trained to spot these type of things and they have every possibility to go wrong."

"And this doesn't?" John demanded.

"No," Sherlock said simply. He looked at Mary. "So you just have to act like you're... interested in me," he said. "Convincingly, if you can manage. Shouldn't be too hard."

"Sherlock!"

"Well, he actually isn't bad looking, John."

John looked sharply at Mary. She grinned.

"Thank you," Sherlock said sarcastically. "You'll need something... a nice dress. It's posh. Reservations."

"Isn't anyone going to ask me if I'm okay with this?" John asked.

"No," Sherlock and Mary said at the same time.

"Besides, Sherlock's going to go dress shopping with me," Mary said. "Then I can come home and surprise you with the dress," she said, laughing quietly.

"What?" Sherlock looked up. "Why do I have to go dress shopp..." he trailed off, narrowing his eyes. "This is one of those 'I do this for you, you do this for me' things, isn't it?" he asked.

Mary smiled. "Good deduction."

Sherlock sighed and shrugged. "If you insist, I guess."

"Oh, I do," she said cheerfully.

Sherlock just sighed again and reached for his scarf.

* * *

"Well?"

Sherlock glanced up from straightening his bow tie. "Well what?"

Mary stood in his bedroom doorway, arms crossed as she stood in the long, sleek, form-fitting deep blue dress. It was low-cut (dangerously so, John would probably say, the anxious prude) with a diamond brooch set where the fabric met.

Mary liked it. John's face would be spectacular, Sherlock thought, but himself personally? He didn't _care_.

"You're supposed to give me a compliment," Mary said patiently.

"I was there when you tried it on the first time," Sherlock replied, looking back in the mirror. "Why do I have to tell you again what I think?"

"Because you didn't tell me what you thought the first time."

"I told you I didn't care."

"That is telling me nothing. You don't tell a woman you don't care."

"Why not?" Sherlock asked, looking at her in the mirror.

"You just don't," she replied.

"But I don't care," Sherlock said truthfully.

Mary rolled her eyes. "You _are_ hopeless," she said, albeit affectionately.

"Hm. Probably shouldn't tell me that at the restaurant," Sherlock said, turning away from the mirror.

"You should probably try a compliment _before_ we get to the restaurant," Mary replied.

Sherlock let his eyes slide down Mary's body and then back up to her face, his head falling the slightest fraction to the side. "That dress accentuates your breasts."

Mary scoffed, but turned away with laughter. "Okay, maybe we shouldn't try compliments."

Sherlock frowned, following her into the bathroom. "What? I complimented the size of your-" Mary reached out and placed her hand against his chest, pushing him over the threshold and closing the door in his face. "... Breasts."

"Don't follow a woman into the bathroom, Sherlock. It's very tactless."

Sherlock rolled his eyes. "You have nothing I haven't seen."

"Oh?" Mary's voice floated through the bathroom door. "Where have you seen it at?"

Sherlock scowled. "A particular woman from a past case... and I have seen naked women besides her, for your information."

"Oh, Irene Adler, is it? John told me about her. Well, I read the blog and then he told me about her," Mary mused. "Were you in love with her?"

Sherlock sniffed and turned away from the door, picking his mobile up from his nightstand. "Love is a chemical defect."

"Uh huh."

Sherlock sighed and slipped his phone in his pocket. "What are you _doing_ in there? You've been in my bathroom for thirty-seven minutes. We should leave in plenty of time and I-"

"Want to fix your hair?" Mary interrupted.

Sherlock frowned and leaned over to glance into his wardrobe mirror. "No. My hair is fine."

"If you want it to be a mess."

"Women like it a mess; what's wrong with it being in a casual disarray? There isn't much I can do with it," Sherlock retorted, running his fingers through it.

Mary opened the bathroom door. Sherlock straightened up and looked at her, although not before she burst into laughter.

Sherlock scowled, again. "Oh, go hail a cab," he said, striding to the bathroom.

"I'll wait on you... darling," Mary added, purely for effect, Sherlock was sure.

Two could play.

"Three minutes, beautiful, and I'll whisk you away to the best night of your life," he said sarcastically, closing the door in her face.

Sherlock smirked as he glanced in the mirror. It wasn't in such a context as implied by his tone, but he was sure that this was going to be a night that neither of them would forget. It was an interesting case, albeit if he had to be _domestic_ to achieve what he wanted. And this was his first case alone with Mary, after all.

She was about to see what being Sherlock Holmes's friend _really_ meant. Murders and mayhem and faked relationships. All in a day's work when you married John Watson, the best friend, ex-flatmate, blogger of _the_ Sherlock Holmes.

(To be fair... Both John and Sherlock had warned her.)

* * *

**Because I need to write another multi!chapter! Not really. This is actually going to end up being a two!shot, or possible three chapters. Nothing terribly long and it's going to be mostly dialogue, and marked as humour for a reason.**

**I like Mary a lot. She makes me suspicious. [NO SPOILERS. I'VE ONLY SEEN EMPTY HEARSE.] But I like her relationship with the boys a lot. Plus, since it's Amanda, that helps a lot.**

**I do not own _Sherlock_. Thank you!**


	2. Chapter 2

"This isn't good," Sherlock muttered.

"Oh, I think it's lovely," Mary said, cutting into her molten cake.

Sherlock flicked his gaze towards her, frowning. "I wasn't talking about the food; I'm talking about the case. I think they're on to us."

"Maybe if you wouldn't act so suspicious," Mary muttered, looking back to her food.

Sherlock looked at her again. "Suspicious? How am I suspicious? I'm not being suspicious."

"Well, you're not eating, either, and this is an expensive restaurant. Who gets a reservation and doesn't eat?"

"_You're_ eating," Sherlock retorted.

"You need to eat."

"I can't eat," Sherlock said, looking back around the restaurant.

"You mean you won't," Mary said.

"No, I mean I can't," Sherlock replied absently, subtly glancing towards their suspects from the corner of his eye.

"Why not?"

"I get nauseous when I eat on a case," Sherlock said. "My stomach doesn't handle digestion well when I'm otherwise occupied."

"Aw. That's cute. Sherlock Holmes gets nervous," Mary said cheerfully.

He looked back at her. "I am _not_ nervous. I'm never nervous."

"You looked nervous when you told John you were still alive. And at my wedding," Mary said, glancing up again. "Your speech."

Sherlock scowled and looked away again.

The rest of dessert went as such until-

"Mary," Sherlock said sharply. "They're leaving."

She looked up. "Hm?"

"They're leaving." Sherlock placed the money on the table and stood, grabbed Mary's hand, and practically dragged her out of the dining area.

"Sherlock!"

"Shh."

"Mr and Mrs Holmes, let us retrieve your coats-" one of the staff started.

"Back in a moment," Sherlock said dismissively.

"Sherlock!" Mary protested again.

"Be quiet..." he muttered, eyes intent on his suspects - figures in the distance already.

Except, when he had converged on them enough to make out the features in their face and they looked directly at him, Sherlock did what he had to protect his façade.

So, he spun around to hide his face, drew Mary close, and pressed his lips against hers.

He'd never kissed anybody before, but the mechanics certainly couldn't be terribly difficult. Mary had tensed up considerably but, after Sherlock slid his hands down to her waist, pressing his fingers into her skin pointedly to tell her _go with the flow_, as such.

She kissed him back. It was very unlike anything that Sherlock had ever experienced. It wasn't entirely un... pleasant. Except that it was Mary and John was probably going to-

There was suddenly a sharp noise and pain exploded from his cheek. He reeled back from the force of the slap, looking at Mary with wide eyes.

"What... what are you doing?" he asked breathlessly, pressing his hand against his cheek and twisting around to look for the suspects. They'd gone, which was good, he supposed. At least they hadn't realised that Sherlock Holmes was on the case yet. "That hurt," he said, looking back at Mary.

"You kissed me!" Mary exclaimed.

Sherlock glanced around himself slightly, half expecting someone to pop out and say _surprise!_ "... So?" he asked shortly.

"I'm _married_," she retorted.

"I know; I was there," Sherlock said, frowning. "But that doesn't explain-"

"You don't go around kissing your best friend's wife, Sherlock!"

Sherlock's frown deepened. "I didn't think you'd have a problem... Was it not satisfactory?"

"It was... it was fine. I prefer John. And you've been smoking," she accused.

Sherlock huffed. "Well, you taste like chocolate."

"That's better than sucking on a cigarette," Mary said.

Sherlock sighed and dropped his hand. "This is ridiculous. At least the suspects didn't totally catch on..."

Mary's laughter broke Sherlock out of his case disappointment; he looked back at her again with yet another frown. "What? Why are you laughing?"

"Your face," she laughed. "It's hilarious."

"You slapped me!"

"With good reason."

"Why are you laughing if you slapped me?!" Sherlock protested.

Mary chuckled and shook her head. "I keep forgetting that you know nothing about human nature. Or boundaries, apparently." She sighed. "Can we get our coats and go home? It's getting chilly."

Sherlock scowled and turned away. "I do not understand you."

Mary smiled, looping her arm with his. "Just don't try to kiss me and we'll be fine, Sherlock."

Sherlock huffed and shoved his hands in his pockets, although he didn't push her away.

* * *

_Three months later_

"Can you make molten lava cake?"

John glanced up. "What?"

"Lava cake. I don't know to make it," Mary said. "Sherlock said you can cook."

Sherlock gave a little 'hm' from his place at the counter, switching out the slides in his microscope.

"I don't know..."

"We'll have to look up a recipe," Mary said. "I had a lovely piece when Sherlock took me out on that case..."

Vague memories filtered back into Sherlock's mind and he licked his lips reflexively. "The chocolate was actually quite good," he muttered, more to himself.

"What was that?" John asked.

Sherlock paused. "... Nothing."

Mary glanced up. "Oh, I forgot to tell him. You didn't, Sherlock?"

Sherlock glanced away from his experiment slowly. "... You know, I think I'll go out," he said, standing abruptly.

John glanced up. "What?" He looked at Mary. "What didn't he tell me?"

Sherlock grabbed his coat, shoving his arms through the sleeves and swiping his scarf from the chair by the door.

"Sherlock kissed me that night," Mary said cheerfully, licking her thumb to turn the page in her book.

_"What?"_

Sherlock hurried down the stairs, buttoning his coat as he went.

"Well, to be fair, it was part of the undercover thing..."

There was a thump from upstairs and Sherlock winced slightly, fluidly jumping the last three stairs to get to the front door.

_"Sherlock!"_

Sherlock closed the door behind him, hurrying towards the street to hail a cab to somewhere where an angry John couldn't find him.

* * *

**Just a little cracky piece that I wanted to write up before ****_His Last Vow_**** airs. I think it would be adorable if Sherlock and Mary went undercover like this and something happened... and then Mary had to hold John back to stop him from pulverising Sherlock. :p**

**I do not own ****_Sherlock_****. Thank you!**


End file.
